Timepiece movements of the aforementioned type are fitted, for example, to calendar watches. The latter include a case in which there is fixed a support, such as a bottom plate, and a display module formed of a central bridge secured to said bottom plate, a date ring, a drive member and a member for positioning the date ring. The module may further optionally include a date correction device.
Conventionally, the drive member is mounted to rotate freely in rotation on the bridge, whereas the date ring is mounted to abut against the bottom plate, free in rotation about the bridge. The positioning member occupies a housing provided for this purpose on the bridge. The axial positioning of these different elements, in the opposite direction to the bottom plate, is generally achieved by a holding plate screwed to the bridge, and extending above the latter and partially above the date ring. An example of this type of bottom plate is given in GB Patent No. 1 471 678. The holding plate, whose shape and dimensions are adapted to the display module, is formed by stamping and bending processes. The manufacturing cost of the holding plate is high since the stamp used for the cutting thereof is itself very expensive. Moreover, assembly of said plate is very expensive as it is one of the final assembly operations of the timepiece, and it is known that the final operations have a considerably higher cost price than the initial or intermediate operations.